package com.rd.student.jiaji.class3.caiyuxin.java7_31;

import java.util.HashSet;

public class RonNum3 {
    public static void main(String[] args) {
        HashSet aset=new HashSet();
        while (aset.size()<20){
            int a= (int) (Math.random()*50);
            aset.add(a);

        }
        System.out.println(aset);

    }
}
